1. Field
The present disclosure relates generally to crawler vehicles for moving tools on the surface of an object. More particularly, the present disclosure relates to a method and apparatus for holding a holonomic or other type of crawler vehicle onto the surface of an object using an electro-permanent magnet.
2. Background
A vehicle may move along the surface of an object to perform various tasks at various locations on the object. Such a vehicle may be referred to as a crawler vehicle. For example, without limitation, a crawler vehicle may be capable of holonomic movement on the surface of an object. A vehicle capable of holonomic movement may rotate while moving in any direction across the surface of an object at the same time.
A crawler vehicle may be configured to carry various tools for performing various tasks on an object. For example, without limitation, a crawler vehicle may be configured to carry a number of tools for performing an inspection on the object, repairing the object, or for performing another desired task or various combinations of tasks on the object.
It may be desirable to hold a crawler vehicle on the surface of an object to prevent undesired movement of the vehicle with respect to the surface of the object. For example, without limitation, it may be desirable for a crawler vehicle to move on inclined or substantially vertical surfaces of an object or in other adverse conditions in which undesired movement of the vehicle may occur. In this case, it may be desirable to hold the crawler vehicle on the surface of the object to prevent undesired slipping movement of the vehicle on the surface or to prevent the vehicle from falling off of the object as the vehicle moves on the surface of the object.
Various systems and methods may be used to hold a vehicle on the surface of an object as the vehicle moves on the surface of the object. Some current examples of such systems and methods include systems and methods for holding a crawler vehicle on the surface of an object using a suction force or a magnetic force.
For example, without limitation, a suction force for holding a vehicle on the surface of an object may be generated by a ducted fan or other appropriate mechanism on the vehicle for propelling air from a channel or other space between the vehicle and the surface to create a suction zone. The use of such a suction force for holding a vehicle on the surface of an object may have several limitations. For example, generating the suction force may consume a relatively large amount of energy and the suction force generated may not be sufficient for holding a vehicle on the surface of an object in some cases.
A magnetic force may be used to hold a vehicle on the surface of an object that comprises a ferromagnetic material. Currently, a magnetic force for holding a vehicle on the surface of an object may be provided by a number of permanent magnets or an electromagnet on the vehicle. Holding a vehicle on the surface of an object using permanent magnets may have several limitations. For example, removing a vehicle comprising permanent magnets from the surface of a ferromagnetic object and transporting such a vehicle comprising permanent magnets may be difficult in some cases. Holding a vehicle on the surface of an object using an electromagnet also may have several limitations. For example, generating a magnetic force by an electromagnet on the vehicle may consume a relatively large amount of energy.
Thus, it would be desirable to have a method and apparatus that take into account one or more of the issues discussed above, as well as possible other issues.